This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 2001-103727, filed Apr. 2, 2001; and No. 2001-143065, filed May 14, 2001, the entire contents of both of which are incorporated by reference.
1. Field of the Invention
This invention relates to a method of forming a pattern and to a method of manufacturing a semiconductor device. In particular, this invention relates to a method of forming a fine pattern on a wafer substrate.
2. Description of the Related Art
The method of manufacturing a semiconductor element involves a patterning step wherein a plurality of materials are deposited on the surface of silicon wafer to form a thin film as a working film (i.e. a film to be worked, the same hereinafter), which is then formed into a desired pattern. In the patterning process of a working film, first of all, a photosensitive material which is generally called xe2x80x9cresistxe2x80x9d is deposited on the working film to form a resist film, and then, a predetermined region of the resist film is subjected to an exposure treatment. Then, the exposure region or non-exposure region of the resist film is removed by a developing treatment to form a resist pattern, which is then employed as an etching mask to dry-etch the working film.
As for the exposure light source to apply a light exposure to a predetermined region of the resist film, ultraviolet ray such as a KrF excimer laser, ArF excimer laser, etc. has been employed in view of throughput. Nowadays however, due to a trend to further increase the fineness in dimension of LSI, the resolution for realizing such a fineness of LSI is required to be that of the exposure wavelength or less, so that the process margin (or tolerance) for exposure such as the tolerance in quantity of exposure, focusing tolerance, etc. is getting too limited to realize such a fineness of LSI. It would be effective, for the purpose of supplementing these process margins, to make thinner the thickness of resist film to improve the resolution. However, the thinner resist process would give rise to another problem that it is difficult to secure a sufficient film thickness of resist film which is necessary for suitably etching the working film.
There has been proposed, with a view to solve the aforementioned problems, a so-called multi-layer resist process, i.e. a method wherein a resist pattern is once transcribed to a silicon oxide film to form a silicon oxide film pattern. According to this method, the silicon oxide film pattern thus formed is employed as an etching mask to dry-etch the working film, thus transcribing the pattern to the working film. As for the silicon oxide film to be employed in this case, there has been employed a spin-on glass which can be made into a film at a low cost by a coating method such as spin-coating without necessitating a vacuum system. However, since this spin-on glass is formed into a film by a coating method, it is difficult to obtain a film of high density as compared with the films to be obtained by a physicochemical method such as a CVD method or a sputtering method. Therefore, the film to be formed using the spin-on glass is poor in etching resistance as compared with a silicon oxide film formed by a physicochemical method, so that etch bias is most likely to be generated on the occasion of etching work of the working film.
A method for forming a pattern according to one embodiment of the present invention comprises:
coating a solution containing a compound having a silicon-nitrogen linkage in the main chain thereof on a surface of a working film to form a mask;
replacing the nitrogen in the mask by oxygen;
forming a resist film on a surface of the mask;
forming a resist pattern by subjecting the resist film to a patterning exposure and to a developing treatment;
transcribing the resist pattern to the mask to form a masking pattern; and
transcribing the masking pattern to the working film to form a working film pattern.
A method for forming a pattern according to another embodiment of the present invention comprises:
coating a solution containing a compound having a semiconductor element-oxygen linkage or a metallic element-oxygen linkage in the main chain thereof on a surface of a working film to form a mask;
forming a resist film on a surface of the mask;
forming a resist pattern by subjecting the resist film to a patterning exposure and to a developing treatment;
transcribing the resist pattern to the mask to form a masking pattern; and
dry-etching the working film with the masking pattern as a mask to form a working film pattern;
wherein an energy beam is irradiated to the mask or to the masking pattern.
A method for manufacturing a semiconductor device according to one embodiment of the present invention comprises:
forming a working film on a surface of a semiconductor substrate having element regions formed therein;
coating a solution containing a compound having a silicon-nitrogen linkage in the main chain thereof on a surface of a working film to form a mask;
replacing the nitrogen in the mask by oxygen;
forming a resist film on a surface of the mask;
forming a resist pattern by subjecting the resist film to a patterning exposure and to a developing treatment;
transcribing the resist pattern to the mask to form a masking pattern; and
transcribing the masking pattern to the working film to form a working film pattern.
A method for manufacturing a semiconductor device according to another embodiment of the present invention comprises:
forming a working film on a surface of a semiconductor substrate having element regions formed therein;
coating a solution containing a compound having a semiconductor element-oxygen linkage or a metallic element-oxygen linkage in the main chain thereof on a surface of a working film to form a mask;
forming a resist film on a surface of the mask;
forming a resist pattern by subjecting the resist film to a patterning exposure and to a developing treatment;
transcribing the resist pattern to the mask to form a masking pattern; and
dry-etching the working film with the masking pattern being employed as a mask to form a working film pattern;
wherein an energy beam is irradiated to the mask or to the masking pattern.